Amodei would be the fourth Republican to enter the race, following retired Navy Cmdr. Kirk Lippold, state Sen. Greg Brower and 2010 Senate candidate Sharron Angle. Lt. Gov. Brian Krolicki announced last week that he would not run.

Three Democrats, including state Treasurer Kate Marshall and former House candidate Jill Derby, are also running in the all-party, winner-take-all election.

Rep. Dean Heller will resign from the House early Monday afternoon just before being sworn in to the Senate. There is no primary, and the election will be open to all qualified candidates who can run on any party line they please.

The state GOP is disputing that in court, however, arguing that only the candidates nominated by the parties&rsquo; central committees should be allowed to run with that party&rsquo;s label.